Compression Problems? head or block?

[smokin150]

ok, heres a new problem... replaced injectors and injection pump due to rough cold start/run and the fact that they had about 225k miles on them. now, i changed all that out when the engine was warm and it fired up and ran great, let it sit for two days and, nada, no change. still ran like it was missing on two or more cylinders. dropped it off at a local shop and had them run a comp test on it, heres the results:

cyl 1 -355psi cold 410 hot
cyl 2 -330psi cold 360 hot
cyl 3 -315psi cold no change hot
cyl 4 - 60psi cold 280 hot
cyl 5 -330psi cold 345 hot
cyl 6 - 45psi cold 195 hot
cyl 7- 200psi cold 250hot
cyl 8-365 cold 370 hot

these are the numbers i got from the mechanic when i picked up the truck this morning he thinks rings or valves are shot, im trying to determine what looks to me like the rings are shot from what might be a popped head gasket or whatever. ive had the coolant checked and there are no trace gasses in the system, and im not mixing oil and water, i am however starting to burn quite a bit of oil and its sooting up real bad, like.... the rear pass side of my truck is now black. i need to get this thing going as quickly as possible as im due to head to the west coast for work in a few weeks and dont want to drive the truck that far knowing i have a problem. any advise would be really helpful. i have a machine shop that can do the work (labor) for free if i can get the engine out and down to him. just want to make sure before i jerk this big engine out.... again.

thanks

 

[Knuckledragger]

Head gasket is broken between cyl 4&6. Every stroke transfers pressure back and forth, hence the similarly low readings. #7 might have worn valves or bad rings. They should have injected a little oil into the cylinder to find out. If compression comes up right away it is rings, if not, it is valves.

 

[riotwarrior]

Head gasket is broken between cyl 4&6. Every stroke transfers pressure back and forth, hence the similarly low readings.

Yuppers I concur with this

#7 might have worn valves or bad rings. They should have injected a little oil into the cylinder to find out. If compression comes up right away it is rings, if not, it is valves.

I dissagree with this...no oil...better to leak down test instead and however if ALL GP's are out a wee squirt may tell u enough...but based on the fact that it's same hot cold I'd think rings...

I'm thinking valve job and quick re-ring bearing job quick n dirty get you by or get a reman or get a known good runner!

Or valve job and HG and just run it till you can do/afford more indepth service.

 

[icanfixall]

I concur with the head gasket blown between 4 & 6 cylinder. Those are the sencond and third cylinders back from the radiater on the drivers side of the engine. You can do a quick and dirty repair by removing that head and replacing the head gasket but know this is a temp fix. Just depends on how deep you want to go when the head is off. All you need is a head gasket, valve cover gasket and a valley pan gasket. Thats the big pan under the intake manifold that is also the intake manifold gasket.